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Bureau of Mines Information Circular/1981 




Alumina Availability— Domestic 

A Minerals Availability System Appraisal 



By Gary R. Peterson, Robert L. Davidoff, 
Donald I, Bleiwas, and Richard J. Fantel 



UNITED STATES DEPARTMENT OF THE INTERIOR 



Information Circular 8861 



Alumina Availability— Domestic 

A Minerals Availability System Appraisal 



By Gary R. Peterson, Robert L. Davidoff, 
Donald I. Bleiwas, and Richard J. Fantel 




UNITED STATES DEPARTMENT OF THE INTERIOR 
James G. Watt, Secretary 

BUREAU OF MINES 



(f 



As the Nation's principal conservation agency, the Department of the Interior 
has responsibility for most of our nationally owned public lands and natural 
resources. This includes fostering the wisest use of our land and water re- 
sources, protecting our fish and wildlife, preserving the environmental and 
cultural values of our national parks and historical places, and providing for 
the enjoyment of life through outdoor recreation. The Department assesses 
our energy and mineral resources and works to assure that their development is 
in the best interests of all our people. The Department also has a major re- 
sponsibility for American Indian reservation communities and for people who 
live in Island Territories under U.S. administration. 






This publication has been cataloged as follows: 



Alumina availibility— domestic. 








(Information circular / Bureau of Mines ; 
Includes bibliographical references. 
Supt. of Docs, no.: 1 28.27:8861 


8861) 






1. Aluminum oxide. 2. Aluminum industry and trade. 1. 
Gary R. , 1948* . II. Title. III. Series: Information circu 
States. Bureau of Minee) ; 8861. 


Peterson, 
ar (United 


TN295.U4 [TN490.A5] 553.4'926 


81-607823 


AACR2 



I or sale by the Superintendent of Documents, U.S. Ciovernnicnt Printinj; Office 
Washinston, D.C. 20402 



PREFACE 



The Bureau of Mines Minerals Availability Program is assessing the world- 
wide availability of nonfuel minerals. The program identifies, collects, compiles, 
and evaluates information on active, developed, and explored mines and deposits 
and on mineral processing plants worldwide. Objectives are to classify domestic 
and foreign resources, to identify by cost evaluation resources that are reserves, 
and to prepare analyses of mineral availabilities. 

This report is part of a continuing series of MAS reports to analyze the avail- 
ability of minerals from domestic and foreign sources. Analysis of supply from 
other minerals is currently in progress. Questions about the MAS program should 
be addressed to Director, Division of Minerals Availability, Bureau of Mines, 2401 
E Street, N.W., Washington, D.C. 20241. 



CONTENTS 

Page Page 

Preface iii Types of deposits — Continued 

Abstract 1 Alunites 12 

Introduction 2 Anortliosites 12 

Acl<nowledgments 3 Dawsonite 12 

Structure of the aluminum industry 5 Refinery technology 13 

Location of domestic refineries Bayer process for bauxites 13 

and smelters 6 HCI leach of clays 13 

Importance of secondary (scrap) recovery Aiunite processing 13 

to the industry 7 Lime sinter of anorthosite 14 

Demand for aluminum 7 Availability of alumina from domestic deposits ... 15 

Estimation of domestic aluminum resources General 15 

and cost data 8 Total recoverable alumina 15 

Types of deposits 12 Potential annual alumina production 15 

General 12 Conclusions 19 

Bauxites 12 References 20 

Clays 12 Appendix 21 

ILLUSTRATIONS 

Page 

1. Location of domestic alumina refineries and aluminum smelters 6 

2. Reserve base and inferred reserve base classification categories 8 

3. Flow chart of evaluation procedure 9 

4. Location of domestic alumina properties 11 

5. Total domestic aluminum resources potentially available at various alumina prices — 

demonstrated resource level 16 

6. Total domestic aluminum resources potentially available at various alumina prices — 

identified resource level 17 

7. Potential domestic annual alumina production in selected years at various alumina prices — 

demonstrated resource level 18 

8. Potential domestic annual alumina production in selected years at various alumina prices — 

identified resource level 18 

TABLES 

Page 

1 . World bauxite production 5 

2. U.S. imports of crude and dried bauxite 5 

3. U.S. imports of alumina 5 

4. Property type, status, and resource data 10 

5. Property type, status, and resource data for anorthosite deposits 11 



ALUMINA AVAILABILITY -DOMESTIC 
A Minerals Availability System Appraisal 

by 

G. R. Peterson,^ R. L. Davidoff,^ D. I. Bleiwas,^ and R. J. Fantel^ 



ABSTRACT 



In order to determine the potential availability of alumina to feed U.S. aluminum 
smelters, tlie Bureau of Mines evaluated 39 domestic mines and deposits of bauxite, 
alunite, and high-alumina clays and found that substantial increases in alumina 
prices would be necessary before nonbauxitic deposits could become competitive 
with bauxite. As part of the study, a price-tonnage relationship was developed indi- 
cating the quantity of alumina that could be produced from known deposits at 
various alumina prices and at a 15-pct discounted cash flow rate of return on the 
required capital investment. All capital and operating costs were calculated In 
August 1980 dollars. 

The domestic bauxite reserve base comprises three operating bauxite mines 
in Arkansas containing some 15.6 million metric tons of recoverable alumina 
(AI2O3). Ferruginous bauxites, clays, and alunltes fall into the subeconomic cate- 
gory of identified aluminum resources, which, at the demonstrated level, contain 
over 4,000 million metric tons of alumina that are estimated to be recoverable. 
Analyses indicate that, at the demonstrated resource level, a total of some 15.6 
million metric tons of alumina, all from three active Arkansas bauxite mines, is 
recoverable at a 1980 price of $0.12 per pound ($264 per metric ton) of alumina. 
A price of approximately $0.26 per pound ($573 per metric ton) of alumina would 
be required for production of the total U.S. resource. Thus, unless new technologi- 
cal breakthroughs occur that could make alternate sources of alumina competitive 
with bauxite, U.S. dependence upon imported bauxite will continue to increase. 



' Mineral economist. 
' Geologist. 

All authors are with the Minerals Availability Field Office, Bureau of Mines, Denver, Colo. 



INTRODUCTION 



Aluminum use exceeds that of all other metals ex- 
cept iron, yet 90 pet of the bauxite ore used in the 
domestic production of aluminum is supplied from 
foreign sources. Through the years, many technological 
improvements have been made in producing aluminum 
from bauxite, but the basic processes have been un- 
changed since the metal first became available in com- 
mercial quantities over 90 years ago. These processes 
consist essentially of surface mining of bauxite, fol- 
lowed by hydrometallurgical processing to produce 
alumina (99.5 pet AI2O3), and then the reduction of the 
alumina to aluminum metal by fused-salt electrolysis in 
a molten bath of fluoride salts {20, p. 1).^ For each 
4.5'* tons of bauxite fed into the alumina refinery, 2 tons 
of alumina are produced, which in turn produces about 
1 ton of aluminum. 

The United States had become highly concerned 
about its growing dependence on imported bauxite and 
alumina by 1970, when the National Materials Advisory 
Board was requested to prepare a report on "Processes 
for Extracting Alumina From Nonbauxite Ores." It was 
felt that a thorough investigation of the potential of 
alternative sources of alumina from domestic ores was 
in the national interest. Processing technologies for 
clays have .been tested by the Bureau of Mines at the 
miniplant stage since July 1973, and processing tech- 
nologies for alunite have been tested in small pilot 
plants by private companies. The Bureau of Mines also 
operated a pilot plant in Laramie, Wyo., to produce 
alumina from anorthosite. Costs developed for this re- 
port were derived from feasibility studies based on 
these tests using state-of-the-art technology. None of 
these processing technologies has yet been developed 
at a commercial scale. 

U.S. concern over growing dependence on foreign 
sources of bauxite intensified with the formation of the 
International Bauxite Association (IBA) in 1974. The 
IBA is comprised of 11 member nations and accounts 
for 75 pet of the world production of bauxite and 48 pet 
of the alumina. The fundamental objective of the IBA 
has been to raise the revenues that its member nations 
receive from their bauxite-alumina industries and, for 
the longer term, to maximize the benefits from their 
respective industries through national control of the 
industry, collective purchasing agreements, and the 
sharing of information and technology {17, p. ill). Amid 
fears that the IBA would attempt to become a strict 
cartel in emulation of the Organization of Petroleum 
Exporting Countries (OPEC), the Bureau of Mines in- 
tensified its investigation of the domestic potential of 
nonbauxitic sources of alumina. 

Currently, the only domestic commercial source of 
alumina is bauxite ore. Although nearly 90 pet of U.S. 
primary aluminum consumption is produced domes- 
tically, domestic mine production represents less than 
10 pet of the bauxite consumed in the United States. 
Some 70 pet of domestic alumina consumption is pro- 
duced in this country, which reflects the growing 
reliance upon both imported bauxite and alumina. 

Dependence upon imported bauxite and alumina for 
the production of aluminum could be alleviated by 
developing alternate sources of alumina in the United 
States. Possible sources include other bauxite (ferrugi- 
nous), clay, alunite, anorthosite, dawsonite contained in 
oil shale, and coal ash. 

The purpose of this study is to evaluate the potential 
availability of cell-grade alumina from domestic re- 



' Underlined numbers in parentheses refer to items in the list of 

references preceding the appendix. 

* Unless otherwise noted, "tons" in the report refers to metric tons. 



sources. Such an evaluation is an inherent element in 
the formulation of a national mineral policy. The 
methodology of this study is as follows: 

1. To estimate capital investments and operating 
costs for each deposit from the mining through re- 
fining stages of production. 

2. To evaluate the quantity and quality of potential 
alumina production from domestic aluminum re- 
sources in relation to physical, technological, 
institutional, and other conditions that affect pro- 
duction from each deposit. 

3. To perform an economic analysis for each deposit. 
The results of these analyses indicate the associ- 
ated tonnages of alumina that could potentially 
be produced at specific prices. 

4. To combine and analyze the price-tonnage rela- 
tionships for all deposits to illustrate the domestic 
alumina production potential at various prices and 
a 15-pct return on investment. 

Results of this study are presented in terms of 
alumina. One assumption of this study is that alumina 
containing the same physical characteristics as alumina 
produced from bauxite can be produced from non- 
bauxitic sources. Preliminary evaluations indicate that 
alumina, meeting current specifications, can be pro- 
duced from alternate sources. In order to increase 
revenues, many bauxite-exporting countries are inte- 
grating forward into the production and export of 
alumina. As this occurs, the United States will be forced 
to import increasing quantities of alumina, rather than 
bauxite, to feed domestic aluminum smelters. The 
higher cost of these imports may make domestic non- 
bauxitic sources of alumina more attractive if process- 
ing technologies can be developed on a commercial 
scale. As a result, the Bureau of Mines is focusing this 
study on potential domestic nonbauxitic sources of 
alumina rather than production of aluminum metal. 

The data collected for this report are stored, re- 
trieved, and analyzed in a computerized component of 
the Minerals Availability System (MAS) {23). An eco- 
nomic analysis is performed on each deposit to esti- 
mate its average total cost of production at a 15-pct 
discounted cash flow rate of return (DCFROR). This 
determines a project's "incentive price" for alumina; 
that is, the price at which a firm would be willing to 
produce alumina over the long-run, where revenues are 
sufficient to cover full costs, including a return on in- 
vestment high enough to attract new capital {1, p. 1-25). 

A total resource availability curve can be constructed 
to show potential alumina production based upon each 
deposit's "incentive price" to produce alumina. The 
total resource availability curve is different from the 
supply curve of traditional economic theory. It is an 
aggregate or sum of total production potential from 
each deposit at a stipulated commodity price that 
covers the full cost of production for each deposit. 
Each deposit's incentive price and its level of output 
(or capacity) are assumed to remain constant over the 
entire producing life of the mine. The curve provides 
a concise, easy to read, graphic analysis of the po- 
tential availability of a commodity at specified long-run 
prices. Annual curves, as presented in this report, are 
the total resource availability curve disaggregated on 
an annual basis. The assumptions inherent in the total 
resource availability curve also apply for the annual 
curves. 

The data required for this study were developed at 
Bureau of Mines Field Operations Centers in Denver, 
Colo., Pittsburgh, Pa., and Spokane, Wash. Personnel 



in these offices obtained tliis information from company 
data, published data, and trips to the mines and de- 



posits. Where necessary, data were calculated by the 
evaluator. 



ACKNOWLEDGMENTS 



The authors wish to express their appreciation to 
Horace F. Kurtz, Bureau of Mines Aluminum Commodity 
Specialist, and Luke Baumgardner, Bureau of Mines 
Bauxite Specialist, for their assistance in determining 
the properties and associated resource tonnages in- 
cluded in this report. The authors also wish to express 
their appreciation to Kenneth Fitzpatrick and Robert C. 
Steckley for their initial efforts in compiling this report. 
The following Bureau of Mines personnel provided 
the majority of data used in this study: 

Eastern Field Operations Center, Pittsburgh, Pa.: 

David G. Hartos 

Joseph A. Hrabik 

C. P. Mishra 

Dale R. Spangenberg 

David R. Wilburn 



Intermountain Field Operations Center, Denver, Colo. 
R. Craig Smith 
Richard A. Salisbury 

Western Field Operations Center, Spokane, Wash.: 
David S. Lindsey 
Burton B. Gosling 
David A. Benjamin 
George B. Gale 

Minerals Availability Field Office, Denver, Colo.: 
Edward H. Boyle, Jr. 
Catherine C. Kilgore 
Jim F. Lemons, Jr. 
Dean P. Reynolds 
Paul R. Thomas 



STRUCTURE OF THE ALUMINUM INDUSTRY 



Currently, the only domestic commercial source of 
primary aluminum is bauxite ore. Bauxite is a rock con- 
taining aluminum hydroxide minerals and impurities. 
Metallurgical-grade bauxite in Arkansas is mined using 
open pit methods with pit depths reaching as much as 
200 feet. In other countries, such as Jamaica and 
Australia, there is very little overburden, and mining is 
little more than an earth-moving operation. Operating 
costs for open pit mining and onsite beneficiation can 
vary greatly depending on transportation methods, de- 
posit location, technology used, scale of operation, and 
the characteristics of the overburden. Mining and bene- 
ficiation costs for domestic bauxite (not including 
transportation) range up to $15.00 per ton of bauxite 
ore (August 1980 dollars). Imported bauxite costs 
approximately $32 per ton including taxes and trans- 
portation. Transportation costs can amount to as much 
as 50 pet of the bauxite price. 

Using the standard Bayer process, bauxite is leached 
with caustic soda under heat and pressure to convert 
the aluminum hydroxides to sodium aluminate, which 
can then be converted to cell-grade alumina (+99.5 pet 
AI2O3). The IBA has estimated that a new "green fields" 
alumina refinery in the Caribbean would be able to 
produce alumina for a total operating cost of approxi- 
mately $275 per ton {10, p. 31). The most important 
production elements from a cost point of view are the 
cost of bauxite (including taxes), return on capital, 
energy, and depreciation. A representative market price 
for domestically produced alumina is currently around 
$255 per ton. 

The alumina, in turn, is reduced to metallic aluminum 
using the Hall-Heroult process. This process uses large 
electrolytic cells and is extremely energy intensive, 
requiring 15,000 to 20,000 kwhr of electricity per ton of 
primary aluminum. Energy can account for 40 to 50 pet 
of the total costs of producing aluminum ingot from 
bauxite (15). Domestic aluminum smelters consumed 
some 78 billion kwhr of electricity in 1978 to produce 
10.4 billion pounds of primary ingot, 10 pet of total 
electricity consumption by U.S. industry in that year 
(8, p. 24). Technological improvements have enabled 
energy usage in aluminum smelting to decrease slightly 
over the past several years. A new process developed 
by ALCOA, under development at the ALCOA plant in 
Palestine, Tex., claims up to a 30-pct saving in energy 
consumption {14, p. 2). 

A representative cost (in August 1980) for smelting 
aluminum metal from alumina, including the cost of the 
alumina, was approximately $0.69 per pound of alumi- 
num ($1,521 per ton) for a typical smelter having a 
capacity in the range of 100,000 to 150,000 tons per 
year of output. Information on the smelting of alumina 
into aluminum is given by Herbert and Castle (5), 
Hoppe (6), and the IBA (8). 

Approximately 86.8 million tons of bauxite was pro- 
duced in the world in 1979 (table 1), of which 22 pet 
was provided by Jamaica, Guyana, and Surinam. 
Australia and Guinea accounted for an additional 46 
pet. In all, the 11 IBA countries accounted for approxi- 
mately 75 pet of the world's bauxite output in 1979. 
The United States imported 13.8 million tons of bauxite 
in 1979 (table 2), 69 pet from the Caribbean. The above 
statistic illustrates the regional character of trade in 
bauxite because of high shipping costs. Most of 
Australia's output is exported to Japan, while bauxite 
produced in West Africa is sold in Europe. 

The United States also imported 3.8 million tons of 
alumina in 1979 (table 3), of which 76 pet originated in 
Australia. The trend towards refining alumina in bauxite- 



producing countries is an important structural change 
in the alumina industry that began about 20 years ago 
and has continued to evolve. In order to reduce ship- 
ping costs and to take advantage of lower quality 
reserves, the aluminum companies began to build 
alumina plants in the bauxite-producing countries to 

Table 1. — World bauxite production 

(1,000 metric tons) 



1976 



1977 



1978 



1979 



27,583 

570 

300 

12,500 

2,400 

530 

1,000 

11,574 

720 

5,000 

3,012 



65,189 



IBA member countries: 

Australia 24,084 26,086 24,293 

Dominican Republic .... 517 583 568 

Ghana 272 244 328 

Guinea 11,316 11,300 12,000 

Guyana 2,686 2,731 2,400 

Haiti 660 588 580 

Indonesia 940 1,301 1,008 

Jamaica 10,312 11,433 11,736 

Sierra Leone 651 745 716 

Surinam 4,587 4,856 5,025 

Yugoslavia 2,033 2,044 2,566 

TotallBA 58,058 61,911 61,220 

Other countries: 

Brazil 827 1,120 1,160 

France 2,330 2,059 1 ,990 

Greece 2,551 2,984 2,630 

Hungary 2,918 2,949 2,899 

India 1,448 1,511 1,653 

Malaysia 660 616 615 

United States 1,989 2,013 1,669 

U.S.S.R 4,500 4,600 4,600 

Others 2,182 2,611 2,593 

Total other countries. . 19,405 20,463 19,809 

World total 77,463 82,374 81 ,029 

Percent IBA 75 75 76 



2,400 
2,000 
2,915 
3,000 
1,600 
700 
1,821 
4,600 
2,589 



21,625 



86,814 
75 



Table 2. — U.S. imports of crude and dried bauxite 

(1,000 metric tons) 

Country 1977 1978 1979 

IBA member countries: 

Australia 19 

Dominican Republic 583 628 551 

Guinea 3,030 3,363 3,924 

Guyana 380 419 425 

Haiti 587 588 572 

Jamaica 6,354 6,448 6,469 

Sierra Leone 80 107 141 

Surinam 1,918 2,259 1,520 

TotallBA 12,932 13,831 13,602 

Other countries: 

Greece 57 3 10 

Trinidad 13 

Brazil 168 

Grand total 12,989 13,847 13,780 

Percent IBA 99.5 99.9 98.7 



Table 3. — U.S. imports of alumina 

(1,000 metric tons) 

Country 1977 1978 

IBA member countries: 

Australia 2,590 2,879 

Guyana 54 30 

Jamaica 629 628 

Surinam 382 382 

Total IBA 3,655 3,919 

Other countries 105 48 

Total 3.760 3,967 

Percent IBA 97 99 



1979 



2,938 

18 

587 

239 



3,782 
55 



3.837 

99 



6 



convert the bauxite before shipping. Shipping costs 
can be cut in half by converting bauxite into alumina 
at the point of bauxite production. The bauxite-produc- 
ing countries have also pushed for more at-home 
alumina production because of the economic contri- 
bution provided by the value added from the further 
processing of bauxite into alumina. Overall, 1 ton of 
alumina is worth approximately 7 tons of bauxite ex- 
ported as raw ore. In 1960, only 10 pet of the total 
world production of alumina was in the lesser de- 
veloped country (LDC) bauxite producers. This per- 
centage has grown steadily, to 34 pet in 1975 {13, p. 14). 

The world aluminum industry is an oligopoly domi- 
nated by six multinational firms: Alcan Aluminum Ltd., 
Aluminum Company of America (ALCOA), Reynolds 
Metals Co., Kaiser Aluminum and Chemical Corp., 
Pechiney Ugine Kuhlmann (PUK), and Swiss Aluminum 
Ltd. (Alusuisse). These companies are fully integrated, 
occupying strategic positions in the industry from raw 
materials production to marketing both the metal and 
end-products. Nearly 50 pet of total world capacity of 
bauxite, alumina, and aluminum is under their control. 
Moreover, through a variety of consortia arrangements, 
one or several of these firms is associated with practi- 
cally all new projects of international significance 
within the industry. 

In addition to these major international firms, there 
are some 50 others whose aluminum operations are 
more restricted in scope but which account for about 
one-fourth of world production capacity for bauxite, 
alumina, and metal. Most of these producers are non- 
Integrated, and some are owned by, or associated with, 



governments or the six large international aluminum 
companies {20, p. 4). Some 19 percent of world 
aluminum production capacity is controlled by the com- 
munist governments, and the balance is accounted for 
by governments of other countries. 

Of the 12 domestic firms producing primary alumi- 
num metal in the United States in 1979, seven owned 
bauxite and/or alumina facilities in the Caribbean area. 
South America, Guinea, or Australia and imported these 
raw materials. 

The six large international aluminum companies 
dominate the market for aluminum metal and metal 
goods. Producers' prices show a high degree of corre- 
spondence and stability. A growing free market exists 
in which metal from nonintegrated producers is offered 
on the London Metal Exchange (LME) on both a spot 
and forward basis. The prices on the LME are tied less 
to the producers' prices and, more commonly, tend to 
fluctuate in consonance with those of the LME quota- 
tions for other nonferrous metals {18, p. 115). Aluminum 
prices stayed remarkably stable, both in current dollar 
and in real terms, throughout the 1960's. Since 1974, 
worldwide inflation, costs for bauxite from IBA member 
countries and the rising costs of energy have been 
factors in causing the aluminum price to increase 
approximately threefold as of August 1980. 

LOCATION OF DOMESTIC REFINERIES 
AND SMELTERS 

Locations of domestic alumina refineries and alumi- 
num smelters including operating facilities and projects 
in the planning or building stages are shown in figure 1. 




Figure 1. — Location of domestic alumina refineries and aluminum smelters. 



The Arkansas operations utilize both locally mined and 
imported bauxite and energy from nearby sources. 
Most domestic alumina refineries are located along the 
Gulf Coast near deep-water ports to receive bauxite 
imported from the Caribbean area, and use natural gas 
or oil from local sources. 

The aluminum smelters are located near large elec- 
tric energy sources because of the large quantities of 
electric power necessary to convert alumina to alumi- 
num. Hydroelectric power is the cheapest form of 
energy for smelters, and, as a result, most smelters are 
located near hydroelectric power installations in the 
Pacific Northwest, the Tennessee Valley Authority (TVA) 
area, and Niagara Falls. Some plants in the East re- 
ceive their energy mainly from coal- or oil-fired thermal 
powerplants or from nuclear installations. Some of 
these smelters have a competitive disadvantage in 
terms of energy cost, but are located close to the 
markets that they serve. 

Some 35 pet of the total domestic aluminum capacity 
is in the Pacific Northwest, which receives hydro- 
electric power from the Bonneville Power Authority 
(BPA). These power contracts with aluminum com- 
panies expire in the mid-1980's, after which the BPA 
is required by law to reassign its hydroelectric power 
to utility companies before making any direct alloca- 
tions to smelters (8, p. 24). Any direct allocations will 
most certainly be at a much higher cost. Moreover, 
there has been an increase in population and industrial 
growth in the area, providing further competition to the 
aluminum industry for energy. Utilities in a position 
to negotiate regular price reviews, like TVA, are tend- 
ing to insist on new prices reflecting costs of coal- or 
oil-fired power stations {13, p. 31). Increased fossil fuel 
costs, environmental restrictions on smelters, and the 
current moratorium on nuclear energy construction are 
problems that affect other domestic regions as well. 

As a result, the industry has been reluctant to expand 
domestic primary production capacity, and companies 
have instead focused their attention towards develop- 
ing "green field" projects offshore in countries such 
as Australia, Brazil, Cameroon, Ghana, and Indonesia. 

IMPORTANCE OF SECONDARY (SCRAP) 
RECOVERY TO THE INDUSTRY 

Recovery of purchased scrap contributes some 25 
pet of the total domestic supply of aluminum. Scrap is 
divided into two main categories: new scrap and old 



scrap. New scrap is generated in the manufacture of 
primary aluminum, semifabricated aluminum mill prod- 
ucts, or finished industrial and consumer products. It 
is aluminum that is not sold in the form of an end-use 
product and includes solids, such as new casting scrap; 
clippings or cuttings of new sheet, rod, wire, and cable; 
borings and turnings from the machining of aluminum 
parts; and residues, drosses, skimmings, spillings, 
sweepings, and foil {20, p. 7). Old scrap comes from 
discarded, used, and worn-out products. It includes 
aluminum engine or body parts from junked cars, used 
aluminum cans and utensils, and old wire and cable. 
The proportion of total dometic metal consumption met 
by the recovery of old scrap amounted to about 10 pet 
in 1979 {11). 

DEMAND FOR ALUMINUM 

Between the years 1975 and 2000, primary aluminum 
demand is expected to increase threefold with an 
average annual rate of growth estimated from 4 pet (72) 
to 5.3 pet {20). This rate of growth is slightly lower than 
the estimated rate of growth for the world as a whole 
over the same period. The United States will likely 
remain the world's largest consumer and one of the 
world's largest producers of aluminum during this 
period. 

U.S. dependence on foreign primary aluminum pro- 
duction is growing. One estimate {28, p. 33) forecasts 
that domestic bauxite production will satisfy a de- 
creasing share of demand, that alumina refining will 
drop from over a 70-pct share in the U.S. market in 
1977 to under 40 pet by the year 2000, and that do- 
mestic aluminum smelting will drop from over 90 pet 
to 80 pet during the same period. At the same time, 
user segments of the domestic market continue to 
grow. In 1979, the major domestic markets, in descend- 
ing order of market share, were building and construc- 
tion, transportation, electrical, consumer durables, and 
machinery and equipment. In housing, the demand is 
growing for roofing, window frames, aluminum siding, 
and insulation. In durables more aluminum is being 
used to improve efficiency and to increase service life. 
In the electrical sector, aluminum is mainly used for 
overhead power transmission lines. In transportation 
the weight of vehicles is decreased by substituting 
aluminum alloys for steel. Finally, in packaging, the 
use of recyclable beverage cans is increasing. 



ESTIMATION OF DOMESTIC ALUMINUM RESOURCES AND COST DATA 



Currently, the only domestic production of alumina 
is from bauxite. Other potential domestic sources of 
alumina include ferruginous bauxites, clays, alunites, 
and anorthosites, none of which are currently being 
exploited. The extraction of alumina from all these 
potential sources, except for anorthosites, is presently 
considered feasible from an engineering view; however, 
none is currently economic. 

For the deposits analyzed in this report, tonnage 
estimates were made at the demonstrated and identified 
resource levels according to the new mineral resource- 
reserve classification system developed jointly by the 
U.S. Geological Survey and the Bureau of Mines (27). 
The demonstrated resource category includes meas- 
ured plus indicated tonnages, and the identified re- 
source category includes measured plus indicated plus 
inferred tonnages. 

Selection of deposits for this study was limited to 
significant, known deposits that have demonstrated or 
identified reserves or resources. Reserves are material 
that can be mined, processed, and marketed at a profit 
under the economic and technologic conditions pre- 
vailing at the time of the evaluation. Resources are 
concentrations of naturally occurring solid, liquid, or 
gaseous materials in or on the Earth's crust in such 
form that economic extraction of a commodity is 
currently or potentially feasible. 

Most reserve and resource tonnage and grade calcu- 
lations presented in this paper have been computed 
partly from specific measurements, samples, or pro- 
duction data and partly from estimations made on 
geologic evidence. Using these estimates, domestic 
aluminum resources were classified into two main 



categories: the domestic bauxite reserve base and 
subeconomic aluminum resources. 

The bauxite reserve base is the in-place portion of 
demonstrated resources from which reserves are esti- 
mated. The reserve base includes resources that have 
the probability of being economically available and is 
composed of resource categories that are economic 
(reserves), marginally economic (marginal reserves), 
and a portion of subeconomic (resources). The position 
of the bauxite reserve base within the classification of 
mineral resources is illustrated in figure 2. 

The domestic reserve base for aluminum is com- 
prised of three bauxite deposits in Arkansas. Bauxite 
deposits in Alabama and Georgia are not included in 
this category because they are mined primarily for 
alumina used in abrasives, chemicals, and refractories. 
Ferruginous bauxites, clays, and alunites fall into the 
subeconomic category of identified resources, shown 
below the reserve base category on figure 2. The sub- 
economic category of identified resources was not con- 
sidered in this study as constituting part of the reserve 
base for aluminum owing to the technological un- 
certainty inherent in processing nonbauxitic sources 
of alumina. As the processing technologies for non- 
bauxitic sources of alumina approach development on 
a commercial scale, these deposits will likely be 
reclassified as part of the reserve base for aluminum. 
The anorthosites fall into the "other occurrences" of 
identified resources. They are categorized as such 
owing to the extremely high energy requirements for 
processing anorthosite using the lime-soda sinter 
process and the unresolved problem of gelation in 
liquid-solid separation. However, anorthosites would 



Cumulative 
Production 



IDENTIFIED RESOURCES 



Demonstrated 



Measured Indicated 



Inferred 



UNDISCOVERED RESOURCES 



Hypothetical 



Probability Range 
-(or)- 



Speculative 



ECONOMIC 



MARGINALLY 
ECONOMIC 



SUB- 
ECONOMIC 



Reserve 



Base 



Inferred 



Reserve 



Base 



+ 



-f 



other 
Occurrences 



Includes nonconventional and low-grade materials 



Figure 2. — Reserve base and inferred reserve base classification categories. 



likely be reclassified as part of the reserve base for 
aluminum as well, pending future technological 
developments. 

After a deposit had been selected for inclusion in the 
analysis, an evaluation of the property was begun. The 
flow of the MAS evaluation process from deposit identi- 
fication to development of supply information is illus- 
trated in figure 3. This flowsheet demonstrates the 
various evaluation stages required to estimate the 
potential availability of domestic alumina. 

For bauxite mines currently in production, the de- 
signed mining and processing production rates and 
capacities and other available production specifics were 
adapted for use in this study. For deposits not in pro- 
duction, appropriate mining and concentrating methods, 
production rates, and other production parameters 
were assumed using operating open pit mines as 
models and current engineering principles. 

Where available, actual mining capital and operating 
costs were used. However, because of a lack of cost 
data available, in many cases costs were either esti- 
mated by standardized costing techniques or derived 
from the Bureau of Mines capital and operating cost 
manual (22). Estimates based on this manual have 
historically shown a reliability within 25 pet of actual 
costs. 

Processing methods and their costs for nonbauxitic 
sources of alumina were estimated using feasibility 
studies based on data obtained from pilot plant and 
miniplant testing. 

Information on the average grades, ore tonnages, 
and different physical characteristics affecting produc- 
tion from domestic alumina deposits was obtained from 
numerous sources, including Bureau of Mines, Geo- 
logical Survey and State publications, professional 
journals, industry publications, annual reports, com- 
pany 10K reports and prospectuses filed with the 
Securities and Exchange Commission, and data made 
available to the Bureau of Mines by private companies. 
The knowledge and expertise of Bureau of Mines per- 
sonnel were utilized in many cases. 

Capital expenditures were calculated for exploration, 
acquisition, development, mine plant and equipment, 



and for constructing and equipping the mill plant. The 
capital expenditures for the different mining and 
processing facilities include the costs of mobile and 
stationary equipment, construction, engineering, facili- 
ties and utilities, and working capital. Facilities and 
utilities (infrastructure) is a broad category that in- 
cludes the costs of access and haulage facilities, water 
facilities, power supply, and personnel accommoda- 
tions. Working capital is a revolving cash fund required 
for operating expenses such as labor, supplies, taxes, 
and insurance. 

The total operating cost of a project is a combina- 
tion of direct and indirect costs. Direct operating costs 
include materials, utilities, direct and maintenance 
labor, and payroll overhead. Indirect operating costs 
include technical and clerical labor, administrative 
costs, facilities maintenance and supplies, and re- 
search. Other costs in the analysis are fixed charges, 
including local taxes, insurance, depreciation, deferred 
expenses, interest payments (if any), and return on 
investment. 

The next step of the evaluation process was to per- 
form an economic evaluation for each property. Using 
the data developed by the Bureau's Field Operations 
Centers, computerized analysis of each property was 
performed. For properties not now in production, all 
capital costs were converted to August 1980 dollars. 
For bauxite mines currently producing, the undepreci- 
ated capital investment remaining in 1980 was calcu- 
lated. All reinvestment, operating, and transportation 
costs were converted to August 1980 dollars. 

The Bureau of Mines has developed the Supply 
Analysis Model (SAM) to determine the deposit's 
primary commodity "incentive price" required to stimu- 
late production and provide a stipulated rate of return 
on the required investment (3). The rate of return used 
in this study is the discounted cash flow rate of return 
(DCFROR), which is most commonly defined as the 
rate of return that makes the present worth of cash 
flow from an investment equal to the present worth of 
all after-tax investments {21, p. 232). For this study, a 
15-pct DCFROR was considered as a necessary rate of 





dentif ication 
and 














Minera 1 ' 

Industries 1 

Location 1 

' System 1 

1 (MILS) 1 

1 data J 

MAS 

compufer 

data 

base 


selection 
of deposits 






















Tonnage 

and grade 

determination 






























\ 




Engineering 

and cost 

eva 1 u at ion 








^ 










1 






r r 




Deposit 

report 

preparation 


MAS 

permanent 

de posit 

files 




r 


1 


r 



























Economic 
factors 



Data 

selection and 

validation 



Financial 

analysis 



Availability 

curve 
generation 






Availability 
curves 



Figure 3. — Flow chart of evaluation procedure. 



10 



return in order to cover the opportunity cost of capital 
plus risk. 

Individual deposit tonnage-price data were then 
aggregated by the SAM to construct the resource avail- 
ability curves presented in this study. The study was 
conducted in constant August 1980 dollars. No escala- 
tion of either costs or prices was included, since it 
was assumed that any increase in costs would be offset 
by an increase in prices. 



Tables 4 and 5 present individual deposit information 
by type of deposit and state, and figure 4 shows the 
location of the properties. The numbers on the map 
(fig. 4) refer to the map index number for the deposit 
shown in tables 4 and 5. Ownership and control data 
for each property are presented in the appendix 
(table A-1). 

Tonnage estimates presented in this study are re- 
ported in metric tons. For converting from metric tons 
to short tons, multiply by 1.10231. 



Table 4. — Property type, status, and resource data^ 



Demonstrated, Identified, 

million tons million tons 

Map Grade, 

Property type index Current pet Mineralized Contained Mineralized Contained 

and name State numbers^ status' AI2O3 material AI2O3 material AI2O3 

ALUNITE 

Pat Property Arizona 30 Exp W 91 11 

A-C Property Colorado 29 Exp 12.00 91 11 

Calico Peak Colorado 27 Exp 12.00 W W 

L-C Property Colorado 28 Exp W W W 

N-G Property Utah 23 Exp W W W W W 

P-V Property Utah 24 Exp W W W W W 

S-X Property . . . '. Utah 25 Exp W W W W W 

White Mountain Utah 26 Exp W W W W W 

Total NAp NAp NAp NAp 186 26 764 101 

BAUXITE 

Alcoa bauxite Arkansas 35 Prd W W W W W 

Quapaw bauxite* Arkansas 36 Prd W W W W W 

Reynolds Arkansas 37 Prd W W W W W 

Total NAp NAp NAp NAp 38 18 = 38 18 

FERRUGINOUS BAUXITE 

Kauai (EC) Hawaii 3 Exp 17.60 44 8 93 16 

Kauai (NE) Hawaii 2 Exp 16.70 66 11 98 16 

Kauai (SE) Hawaii 1 Exp 17.40 37 6 54 9 

Maui Hawaii 4 Exp 22.20 43 10 

Columbia County Oregon 8 Exp W W W W W 

Salem Hills bauxite Oregon 9 Exp W W W W W 

Washington-Multnomah Oregon 7 Exp W W W W W 

Cowlitz-Wahiakum Washington 6 Exp W W W W W 

Total NAp NAp NAp NAp 224 47 378 77 

CLAY 

Saline County clay Arkansas 38 Exp 35.00 75 26 100 35 

lone clays California 21 Ppd 26.00 49 13 162 42 

Americus Georgia 42 Dev 26.70 2,400 641 3,600 961 

Sandersville Macon Georgia 43 Dev 26.60 2,400 638 3,600 958 

Wrens kaolin Georgia 44 Dev 29.20 9,600 2,803 12,000 3,504 

Bovill clay Idaho 13 Prd 19.50 21 4 43 8 

Canfield/ Rogers Idaho 14 Ppd 14.50 12 2 204 30 

Olson/Stanford Idaho 12 Exp 17.50 114 20 114 20 

Union County clays Illinois 39 Ppd 28.30 98 28 294 83 

North District fireclay Missouri 34 Exp 33.00 450 149 450 149 

Wilcox kaolin Mississippi 41 Dev 27.50 11 3 50 14 

Belt clay Montana 18 Ppd 26.10 28 7 

Kiowa County clays Oklahoma 32 Exp 23.00 53 12 

Hobart Butte Oregon 11 Ppd 24.40 64 16 94 23 

Molalla clay Oregon 10 Exp 19.10 67 13 94 18 

Ackerman kaolin Tennessee 40 Dev 26.70 11 3 54 14 

Medley kaolin Texas 31 Exp 26.00 6 2 23 6 

Monkton kaolin Vermont 50 Ppd 24.20 17 4 33 8 

North Bennington Vermont 51 Ppd 23.30 9 2 11 3 

Cowlitz clay Washington 5 Exp 19.70 137 27 

Total NAp NAp NAp NAp 15,404 4,367 21,144 5,922 

Grand total NAp NAp NAp NAp 15,852 4,458 22,324 6.118 

W Withheld to avoid disclosing individual company confidential data. NAp Not applicable. 

' All mines/deposits are mined or proposed to be mined by open pit methods. 

^ Map index numbers refer to map on figure 4. 

' Prd— Producer; Dev— Developed deposit; Exp— Explored deposit; Ppd— Past producer. 

* Quapaw currently produces bauxite for chemical uses only. This bauxite is amenable to processing into alumina if needed. 

' Domestic reserve base. 



11 




20 



46* 






49 



45*, 



30 



32 
**33 



34* 



, 35, 36, 37 



^39 i 



• 40 



4H 



38 



43 



\42 



44 



LEGEND 

/V Active bauxite operations 

* Ferruginous bauxite deposits 

• Clay deposits 

■ Alunite deposits 

♦ Anorthosite deposits 







\ 3, 






> 


c 


1,2, 


3 <c> 


.\ 






'<^ 






Hawaii 


c> 





Figure 4. — Location of domestic alumina properties. 



Table 5. — Property type, status, and resource data for anorthosite deposits^ 



Demonstrated, 
million tons 

Map Grade, 

Index Current percent Mineralized Contained 

Property name State numbers^ status^ AI2O3 material AI2O3 

San Gabriel California 22 Exp 27.00 16,200 30,000 

Boehls Idaho 17 Exp 29.00 1,000 290 

Cedar Creek Idaho 16 Exp 29.00 1,600 464 

Goat Mountain Idaho 15 Exp 29.00 2,000 580 

Stillwater anorthosite Montana 19 Exp 30.00 4,000 1,200 

13th Lake anorthosite New York 49 Dev 25.50 10,200 2,601 

Adirondack Park New York 48 Exp 25.50 350,000 89,250 

Carthage anorthosite New York 46 Exp 25.50 500 128 

Rand Hill anorthosite New York 47 Exp 24.50 2,660 652 

Raggedy Mountain Gabbroic Oklahoma 33 Exp 28.00 1,380 386 

Corry Peat Products Pensylvania 45 Exp 25.50 1,000 255 

Laramie Range Wyoming 20 Exp 27.00 65,000 17,550 

Total NAp N Ap NAp NAp 469,340 121 ,456 

NA Not applicable. 

' Anorthosites are not included in the reserve base but have potential for future production. 

^ Map index number refers to map on figure 4. 

' Exp— Explored prospect; Dev— Developing prospect; all deposits are proposed to be mined by open pit methods. 



Identified, 
million tons 



Mineralized 
material 



Contained 
AhOa 



8,100 
2,000 
3,200 
4,000 
8,000 
10,200 

350,000 

500 

2,660 

5,000 

2,000 

130,000 



577,560 



60,000 

580 

928 

1,160 

2,400 

2,601 

89,250 

128 

652 

1,400 

510 

35,100 



150,909 



12 



TYPES OF DEPOSITS 



GENERAL 

Aluminum, the third most abundant element in the 
Earth's crust, occurs in combined form in virtually 
every geologic setting. In this study, a deposit is con- 
sidered as a potential source of alumina if it contains 
aluminum significantly greater than the average crustal 
abundance, may be amenable to chemical separation 
on a commercial scale, and has future economic 
potential. Currently, only bauxite ore is mined and 
refined to alumina and smelted to metallic aluminum. 
One of this study's criteria for a potential alumina 
source is that smelting grade alumina can be produced. 

General types of deposits analyzed in this study are 
described in the following paragraphs. 

BAUXITES 

Bauxite, the principal ore of aluminum, is composed 
of aluminum hydroxide minerals w/ith impurities of free 
silica, clay, silt, and iron hydroxides (24). Bauxite is 
formed as a residual soil in humid, tropical, or sub- 
tropical regions where good drainage is present. Under 
the extreme weathering conditions common to tropical 
climates, the iron and aluminum silicates are decom- 
posed and'Silica, with many other elements, is removed 
by leaching through downward percolation of water. 
Bauxite deposits typically assay 28 to 55 pet AI2O3. 

Domestic metallurgical-grade bauxite deposits ana- 
lyzed include the ALCOA, Quapaw, and Reynolds 
deposits of Arkansas and the ferruginous bauxite de- 
posits located in Oregon, Washington, and Hawaii. 

CLAYS 

Clays are fine-grained, earthy materials composed 
mainly of hydrous aluminum silicates (24). They may 
be predominantly one clay mineral or mixtures of clay 
minerals and nonclay materials. Clay minerals include 
kaolin, montmorillonite, illite, and halloysite. Domesti- 
cally, the best clays are high-alumina kaolinites formed 
by chemical weathering of crystalline rocks. Kaolin 
clays are the only clays considered in this study as a 
potential raw material for aluminum based upon known 
processing technology. A typical representation of 
kaolinite deposits in this study are those located in 
Georgia, which average 28.3 pet AI2O3. 

Twenty clay deposits were analyzed in this study, 
including those found in Arizona, California, Georgia, 
Idaho, Illinois, Mississippi, Missouri, Montana, Okla- 



homa, Oregon, Tennessee, Texas, Vermont, and 
Washington. 

ALUNITES 

The mineral alunite is a sulfate of potassium and 
aluminum formed by sulfateric action of hot acid waters 
upon feldspathic rocks. Alunite deposits can occur as 
fine-grained and massive rock but can also be altered 
under similar conditions to alunite with clays and, in 
some cases, to mostly kaolinitic clays. 

Alunite contains an average of 37 pet AI2O3, but the 
eight deposits analyzed in this study are diluted with 
country rock to as little as 11 pet AI2O3. These de- 
posits are located in Arizona, Colorado, and Utah. 

ANORTHOSITES 

Anorthosite is a plutonic igneous rock composed 
almost entirely of plagioclase feldspar, which is usually 
labradorite. Labradorite is a lime-soda aluminosilicate, 
a plagioclase feldspar intermediate between anorthite 
and albite. Anorthosites are usually large rock bodies 
exposed in the cores of older mountain ranges. As a 
group they constitute possibly the largest potential 
resource of aluminum, with grades averaging about 
27 pet AI2O3; unfortunately, current state-of-the-art 
technology does not provide a feasible process for 
alumina recovery from anorthosites. Therefore, anor- 
thosite deposits are not included in this study's analysis 
of availability from domestic resources. A list of anor- 
thosite deposits is given in table 5. (See figure 4.) 

DAWSONITE 

A potentially economic occurrence of the mineral 
dawsonite is located in the so-called oil shales of the 
Piceance Creek Basin in Colorado. Oil shale aver- 
ages some 12 pet dawsonite, which in its pure form 
Na3AI(C03)3.2AI(OH)3 contains 35.4 pet AI2O3 and is 
considered 65 to 75 pet recoverable (7). However, as 
a percentage of whole rock, recoverable alumina from 
dawsonite amounts to only 2 to 3 pet. While oil shale 
resources may amount to billions of tons, demonstrated 
reserves of dawsonite have not yet been delineated, 
and any economic recovery of alumina is entirely de- 
pendent upon the mining of oil shale; therefore, daw- 
sonite can only be considered as a potential aluminum 
resource prior to development of an oil shale industry. 



13 



REFINERY TECHNOLOGY 



The physical nature and chemical composition of 
potential ore dictate the type of extraction technology. 
All the refining techniques considered in this report 
require chemical leaching of ore followed by the pre- 
cipitation of an alumina-bearing intermediate product. 
Usually, the intermediate product, hydroxide or chloride 
(depending on the extraction process), is then calcined 
to aluminum oxide (alumina). 

The following processes have been selected for 
treatment of the various aluminum-bearing resources 
included in this study. 

BAYER PROCESS FOR BAUXITES 

High-silica bauxites presently mined in Arkansas are 
amenable to the combination Bayer process, whereas 
the ferruginous bauxite of Hawaii and the Pacific North- 
west could possibly use a modified classic Bayer 
process. Approximately 2 pet of mineralized material at 
the demonstrated level may be processed using this 
technology. 

In the classic Bayer process, aluminum and other 
soluble elements in bauxite are dissolved at elevated 
temperatures and pressures in a hot, strong alkali 
solution, generally NaOH, to form sodium aluminate. 
After separation of the "red mud" tails, the sodium 
aluminate solution is cooled and seeded, and aluminum 
trihydrate is precipitated in a controlled form. The 
trihydrate is dewatered and calcined to the anhydrous 
crystalline form, alumina. This is the most suitable form 
for later use in the electrolytic reduction to aluminum 
metal using the Hall-Heroult process. This form is 
traded commercially and can be used in feedstock, 
abrasives, or chemical alums. 

High-silica bauxites such as those from Arkansas 
require additional processing for optimum separation 
of alumina. The Combination Process is applied to the 
red mud residue from the standard Bayer processing 
to extract additional amounts of alumina and to recover 
sodium values [26). 

The additional extraction step consists of mixing the 
red mud with limestone and sodium carbonate, and 
then sintering the mixture. The silica is converted to 
calcium silicate and the residual alumina to sodium 
aluminate. The sintered products are water leached to 
produce sodium aluminate solution, which is filtered to 
remove undigested solids and rejoined with the main- 
stream from Bayer processing for precipitation or 
separately precipitated. The residual solids (brown 
mud) are slurried to a waste lake. 

The purification standards required for producing 
refined alumina from the raw ore are very strict. Under 
present technology, substitutes for bauxite must yield 
aluminum at least equal in quality to that obtained from 
bauxite. Any increase in impurities will decrease the 
recovery efficiency of the electrolytic cells (used in 
reducing alumina to aluminum), and impurities may be 
carried through to the metal. 

HCI LEACH OF CLAYS 

High-alumina kaolinitic clays may be a preferred raw 
material for alumina production in place of bauxites. 
They are abundant, have a comparatively high alumina 
grade, have a high ratio of acid-soluble alumina to 
impurities, and do not consume large amounts of 
reagents during processing (2, p. 219). 

Based on Bureau of Mines test-scale processing of 
clays, optimum results are obtained by hydrochloric 
acid extraction with HCI gas-induced crystallization 



(16). Approximately 97 pet of the mineralized material 
studied at the demonstrated resource level may be 
amenable to such technology. 

In this process, the prepared clay ore is calcined to 
change the alumina into an acid-soluble form. Calcina- 
tion also removes free and combined water and 
destroys any organic matter in the clay as mined. The 
calcined clay is then digested with hot hydrochloric 
acid at atmospheric pressure to produce aluminum 
chloride-rich liquor. The liquor is settled and filtered, 
and the washed mud residue is sent to waste ponds. 
Dissolved iron is removed by solvent extraction and 
thermal conversion and then reacted with calcined clay 
to form aluminum chloride and iron oxide, which is 
sent to the waste pond. The iron-free liquor is con- 
centrated by evaporation and then the alumina crystal- 
lized as aluminum chloride hexahydrate by HCI gas. 
The crystals are separated mechanically from the 
mother liquor and then decomposed thermally to the 
product alumina. Reagents are recycled and waste heat 
recovered under the most efficient operating conditions. 

Although the potential recovery of alumina from 
kaolin c'ays was investigated in this study based on 
hydrochloric acid extraction using HCI gas induced 
crystallization technology tested at the "miniplant" 
level, there are other existing experimental tech- 
nologies for the extraction of alumina from kaolin clays. 
A hydrochloric acid process has been studied in detail 
by Anaconda, which operated a successful pilot plant 
during the 1960's capable of extracting 6.4 tons per day 
of alumina from kaolin {13, p. 81). The Bureau of Mines 
investigated a nitric acid extraction process during 
miniplant testing in 1975 (2, p. 247); Arthur D. Little, 
Inc., also investigated a nitric acid process. 

ALUNITE PROCESSING 

Before chemical processing, the raw alunite ore is 
crushed, ground, and sized, the prepared ore is first 
fed to a roaster where free and combined water are 
volatilized. The hot calcine is then fed to a reducing 
roast where most of the sulfur is removed. The removed 
sulfur passes to a sulfuric acid plant in the proposed 
commercial-scale operation. Some of the sulfur re- 
mains bound with potassium. The reduced calcine is 
again roasted to oxidize iron and other sulfides so that 
they do not interfere with the modified Bayer process 
recovery of alumina. The temperatures and residence 
time for the different roasts must be carefully con- 
trolled in order to remove water and most of the sulfur, 
and to avoid converting alumina to a caustic insoluble 
form. 

Potassium sulfate is leached from the reoxidized 
calcine by dissolution in hot, dilute recycled potassium 
sulfate solution and potassium hydroxide. The potas- 
sium sulfate product may be processed in a separate 
circuit to manufacture fertilizer. 

The solids left after leaching sulfate and potassium 
are about 20 pet AbOi, and the balance is mainly silica 
with small amounts of iron and titanium oxides. This 
slurry is washed and then treated in a modified Bayer 
process to recover alumina. Leaching in lime and 
soda solution to separate alumina as the trihydrate and 
then decomposition of the trihydrate to the product 
alumina follow the conventional Bayer process. Waste 
heat and reagents are recycled for operating efficiency 
with the additional recovery of sulfate and potassium 
in a commercial-scale operation. 

A commercial-scale plant for the extraction of alunite 
has been operated in the Soviet Union, and small pilot 



14 



plants have been operated in Mexico and in Golden, 
Colo. The Alumet Consortium partnership, comprised 
of Earth Sciences Inc., National Steel Corp., and South- 
wire Corp., reported favorable results from tests at 
their pilot plant in Golden, which was shut down in 
1978. 



LIME SINTER OF ANORTHOSITE 

The largest domestic potential resources of alumina 
are contained in anorthosite rock bodies {4, p. 2). 
Anorthosite is an almost monominerallic igneous rock 
of plagioclase feldspars. The feldspars are near the 
calcium-rich end of the soda-lime isomorphous series. 
These deposits are a potential source of virtually un- 
limited amounts of alumina, if the alumina can be 
extracted on a competitive basis. The alumina is in a 
very strong chemical combination with silica, calcium, 
sodium, and potassium. Major amounts of limestone 
and fuel, such as coal, are required for the processing 
of anorthosite. A large amount of solid material similar 
to cement clinker is the main byproduct of commercial- 
scale processing of anorthosite. 

The separation of alumina from anorthosite by sinter- 
ing with lime and soda was tested by the Bureau of 
Mines at a pilot-plant scale {19). For the processing 
considered- here, the mined, crushed, and classified 
anorthosite ore is mixed with water and lime, then is 
dried, pelletized, and sintered. The sintering step ties 
the alumina with the alkalis, combines silica into 
dicalcium silicate, and produces large amounts of CO2 



flue gas. The sinter product is soaked in a rotary 
calciner to produce self-disintegrating crystal. Leach- 
ing is by a concentrated sodium carbonate solution 
with approximately 75 pet of the contained alumina 
extracted. Gelation in the leaching step is a technical 
problem that has delayed development of alumina 
extraction from anorthosite. Almost two-thirds of the 
feed weight is removed as solid waste after leaching. 
The disposal of such large amounts of solid waste may 
present significant problems. Under proper market con- 
ditions, however, this solid waste could possibly be 
processed to portland cement. 

The silica is next removed from the pregnant liquor 
by seeding. The desilicated solution is seeded and 
carbonated with washed flue gas to precipitate alumi- 
num trihydrate. Coarse aluminum trihydrate crystals 
are separated, washed, and dewatered. Calcining de- 
composes the crystals to the alumina product. Waste 
heat and reagents are recovered and washed flue gas 
used in the process. 

Although the problem of gelation during separation 
of alumina from anorthosite appears to have been 
solved on a laboratory scale, larger scale work has not 
confirmed the laboratory studies, necessitating further 
Bureau of Mines research in this area. For this reason, 
plus the extremely high energy requirement of the 
lime-soda sinter technique, this process is not con- 
sidered feasible on a commercial scale. Because of 
their, enormous potential, anorthosite deposits are 
listed on table 5, but they were not included in this 
analysis to determine the domestic potential avail- 
ability of alumina. 



15 



AVAILABILITY OF ALUMINA FROM DOMESTIC DEPOSITS 



GENERAL 

Alumina availability in this study was determined at 
the demonstrated and identified resource levels. Ton- 
nages potentially available at these levels from each 
deposit are shown in table 4. 

The bauxite reserve base, established to estimate 
aluminum reserves and resources, is that portion of 
demonstrated resources that has a probability of eco- 
nomic availability (27). The subeconomic resources of 
aluminum-bearing materials analyzed in this study may 
have a probability of economic availability in the future 
depending upon the economics of the industry and 
technological improvements but, as yet, are not con- 
sidered part of the reserve base for aluminum. 

For 1980, the domestic bauxite reserve base was 
estimated to be 38 million tons of ore containing 18 
million tons of alumina, of which approximately 15.6 
million tons is estimated to be recoverable. Total 
resources at the demonstrated resource level (Arkansas 
bauxite plus subeconomic alternate sources) were esti- 
mated to be about 4,500 million tons of contained 
alumina with slightly over 4,000 million tons estimated 
to be recoverable. Total resources at the identified 
resource level are approximately 6,000 million tons of 
contained alumina, with a little more than 5,500 million 
tons considered to be recoverable. 

Resource availability curves have been developed 
to illustrate potential total and annual domestic alumina 
production based upon each deposit's "incentive price" 
for alumina. The computed incentive price equals an 
individual mine's average total cost of production over 
its entire life including a 15-pct rate of return on 
investment. These curves show the quantity of alumina 
that is recoverable after all mining and processing 
losses. Approximately 93 pet of domestic alumina re- 
sources are estimated to be recoverable using state- 
of-the-art technology. 

This study is a static analysis based on the current 
bauxite reserve base and identified resource estimates 
and on proven and experimental technology. However, 
as exploration and development yield additional knowl- 
edge of grades and tonnages, and as experimental 
processing technologies become feasible on a com- 
mercial scale, portions of this material may be reclassi- 
fied. Historically, domestic mineral resources that can 
be produced economically have increased because of 
exploration and technologic improvements that enable 
the mining of lower grade materials or the processing 
of materials previously considered as waste. Also, as 
prices for alumina produced from bauxite increase, 
nonbauxitic sources of alumina will likely become more 
competitive in the future. The analyses of nonbauxitic 
sources of alumina in this study are based on nascent 
technologies, which will likely be proven at a com- 
mercial scale in the future, thereby improving the 
competitive position of these sources. 

In order to determine the quantity of alumina that 
could potentially be produced on an annual and 
cumulative basis over the life of each deposit and the 
cost of this production, the following assumptions have 
been made: 

1. Development of each deposit began in 1980. 

2. Each operation can produce at full operating ca- 
pacity throughout the life of the mining operation. 

3. Each operation will be able to sell all of its output 
at the alumina price required to receive at least 
the desired 15-pct rate of return. 



The assumptions used for this study were based 
upon the desire to determine potential availability of 
domestic alumina under an emergency situation. As a 
result, time lags involved in filing environmental impact 
statements and receiving necessary permits, financing, 
etc., are not included in this study. Under existing laws 
and regulations, production from some deposits in- 
cluded in this study would likely be limited by environ- 
mental, political, legal, or other constraints. For ex- 
ample, it is highly unlikely that the State of Hawaii 
would allow the mining of bauxite on the picturesque 
islands of Maui and Kauai, for obvious reasons. 



TOTAL RECOVERABLE ALUMINA 

For this study, the portion of the resource availability 
curves representing potential alumina production from 
resources other than Arkansas bauxite mines have 
been shaded in order to emphasize the technological 
uncertainties inherent in estimating the cost of pro- 
ducing alumina from nonbauxitic sources based on 
miniplant test date. The shaded areas is not intended to 
represent a confidence interval. The portion of the 
curves accounted for by the Arkansas bauxite proper- 
ties is not shaded since the Bayer process technology 
is well established. Figure 5 shows total recoverable 
alumina at various alumina prices including at least a 
15-pct rate of return. Analyses indicate that, at the 
demonstrated resource level, a total of 15.6 million tons 
is recoverable from Arkansas bauxite properties that 
are currently producing, and 4,114 million tons from 
nonbauxitic and ferruginous bauxite deposits that have 
been explored. At a 1980 price of $0.12 per pound 
($264 per ton), all 15.6 million tons of alumina from 
Arkansas bauxite deposits are recoverable. At an 
alumina price of $0.26 per pound ($573 per ton), 4,130 
million tons of alumina is potentially recoverable. At 
these prices, all properties could produce alumina and 
earn at least a 15-pct return on investment. 

Potential total production of alumina at the identified 
resource level is shown in figure 6. Analyses indicate 
that a total of 15.6 million tons of alumina is recover- 
able from Arkansas bauxite properties that are currently 
producing, and 5,649 million tons is recoverable from 
explored nonbauxitic and ferruginous bauxite deposits. 

In general, the lower cost deposits on both the curves 
are bauxitic, followed by a mix of ferruginous bauxite, 
clays, and alunite deposits. The clay deposits form the 
majority of the resource tonnage on both curves. (See 
table 4.) 



POTENTIAL ANNUAL ALUMINA 
PRODUCTION 

Annual production curves for alumina at various price 
levels, including at least a 15-pct rate of return, are 
illustrated in figure 7 at the demonstrated resource 
level. The curves are based on current and expected 
production capacities at producing mines and non- 
producing deposits. The curves were generated in 
order to reflect the fact that an increase in production 
cannot be obtained immediately. The time required to 
initiate production depends on factors such as the 
relative location of the deposit and the necessity for 



16 



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1^1^ Shaded areas highlight the technological uncertainties of 
'■■'■''■'■■■ producing alumina from nonproducing deposits 



I 



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TOTAL RECOVERABLE ALUMINA, million tons 

Figure 5. — Total domestic aluminum resources potentially available at 
various alumina prices — demonstrated resource level. 



5,000 



exploration, development, and plant construction. Thus, 
an examination of the curves indicates that if all non- 
producers had begun preproduction development in 
1980, very little increase in production would be noted 
immediately. Substantial increases could occur by 
1983, when production could be as much as 8.2 million 
tons of alumina per year. Full production could be 
realized by 1986, when 10.5 million tons of alumina 
could be produced. After 1986, production of alumina 
from all sources would appear to slowly decline until 
2005, which is also when the exhaustion of known 
low-priced bauxite deposits would occur. This is re- 



flected in an upward shift of the curve from the $0.08 
per pound ($176 per ton) range in 1980 to the $0.15 
per pound ($331 per ton) range in 2005. 

Alumina production from domestic bauxites could be 
approximately 1.15 million tons in 1986. Domestic 
demand for alumina in that year is expected to be 
almost 20 million tons (20, derived from aluminum de- 
mand forecast in its table 11). Thus the share of 
alumina production from domestic bauxite will continue 
to drop from the current 10 pet to 5.8 pet by 1986. 

Annual production curves at the identified resource 
level are illustrated in figure 8. 



17 



1 — r 



T — I — r 



1 — r 



0.30 



Total alumina recoverable from domestic alumina resources; 
Identified resource level; 15-percent rate of return 



Shaded areas highlight the technological uncertainties of 
producing alumina from nonproducing deposits 





0.25 



< o .10 - 







10 20 30 40 50 

RECOVERABLE ALUMINA, million tons 



J L 



J I I I L 



1,000 2,000 3,000 4,000 

TOTAL RECOVERABLE ALUMINA, million tons 



5,000 



6,000 



Figure 6. — Total domestic aluminum resources potentially available at 
various alumina prices — identified resource level. 



18 



30 


1 1 1 1 1 1 1 1 1 1 




1980 




Costs include 15-percent rate of return on 


20 


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10 

n 


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ANNUAL RECOVERABLE ALUMINA, oiillion tons 



Figure 7. — Potential domestic annual alumina produc- 
tion in selected years at various alumina 
prices — demonstrated resource level. The 
shaded areas highlight the technological 
uncertainties of producing alumina from 
nonproducing deposits. 



60 


1 1 


— 1 \ — 1 r- 

1980 


— 1 1 — 


-1 1 1 


' — 1 — 1 — 1 — r 


- 




Costs 


include i5-percent 


rate of 


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40 


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1 — I — I r 



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T 1 1 1 1 1 \ 1 1 r 

2005 




J I I I I I I I I I I I I I I 

I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 
ANNUAL RECOVERABLE ALUMINA, million tons 



Figure 8. — Potential domestic annual alumina produc- 
tion in selected years at various alumina 
prices — identified resource level. The 
shaded areas highlight the technological 
uncertainties of producing alumina from 
nonproducing deposits. 



19 



CONCLUSIONS 



The demonstrated and identified resource levels for 
domestic alumina are comprised of 31 and 39 proper- 
ties, respectively. These properties are inclusive of 
three different types of deposits; bauxites (primarily 
ferruginous bauxites), clays, and alunites. All of these 
properties were analyzed to determine the quantity of 
alumina available from each deposit and the alumina 
price required to provide each operation with a 15-pct 
rate of return. The 1980 domestic bauxite reserve base 
(demonstrated resource level) is 18 million tons of 
alumina, of which approximately 15.6 million tons are 
recoverable. Subeconomic aluminum resources at the 
demonstrated level amount to 4,440 million tons of 
alumina, of which 4,114 million tons of alumina is con- 
sidered recoverable. Total contained alumina at the 
identified resource level is 6,117 million tons, with 5,665 
million tons of alumina considered to be recoverable. 

For those properties classified as subeconomic re- 
sources, an alumina price of $0.26 per pound ($573 
per ton) would be required if all properties, producing 
and nonproducing, were to produce alumina and re- 
ceive at least a 15-pct rate of return. Including those 
properties at the identified resource level, the needed 
alumina price would be $0.50 per pound ($1,102 per 
ton), which is almost 5 times the current price. 

There are only three Arkansas bauxite deposits 
currently comprising the U.S. bauxite reserve base, and 
the amount of alumina contained in these deposits is 



small. In fact, the alumina contained in these three 
deposits comprises less than 1 pet of total domestic 
alumina resources. Although the Bureau of Mines, in 
conjunction with the private sector, is continually re- 
searching alternative methods of processing alumina 
from other known aluminum-bearing deposits (that is, 
alunite, clays, anorthosites), this study indicates that 
these deposits as yet cannot economically compete 
with the rest of the world's huge economic bauxite 
reserves. As a result, the United States will likely con- 
tinue to import the majority of the bauxite and alumina 
necessary to meet current and projected aluminum 
consumption at least through the year 2000. 

Domestic nonbauxitic resources represent a large 
potential source of alumina. Continuing efforts by the 
Bureau of Mines and cooperating companies to im- 
prove technologies for recovering alumina from these 
sources will be necessary to provide stable supplies 
of alumina in the next century. Supplies of alumina 
from nonbauxitic sources would be required much 
sooner if the Nation were to face an embargo or cutoff 
of bauxite and alumina supplies from foreign sources. 
Furthermore, the existence of the ongoing U.S. program 
to develop new technologies to recover alumina from 
nonbauxitic sources could restrain foreign bauxite 
producers from raising prices above the point that 
would make domestic sources of alumina competitive 
with them. 



20 



REFERENCES 



1. Arthur D. Little, Inc. Economic Impact of Environmental 
Regulations on the United States Copper Industry. Rept. to 
the U.S. Environmental Protection Agency, January 1978, con- 
tract 68-01-2842; reproduced and distributed by the American 
Mining Congress, Washington, D.C. 

2. Bengtson, K. B. A Technological Comparison of Six 
Processes for the Production of Reduction-Grade Alumina 
From Non-Bauxite Raw Materials. Met. Soc. AIME, Paper 
LM-79-14, 1979, pp. 217-281. 

3. Davldoff, R. L. Supply Analysis Model (SAM): A Minerals 
Availability System Methodology. BuMines IC 8820, 1980, 
45 pp. 

4. Fitzpatrick, K. T. The Economics of Alumina Production 
From the Laramie Range Anorthoslte, Albany County, Wyo- 
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1979, 95 pp. 

5. Herbert, I. C, and J. F. Castle, Extractive Metallurgy, 
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6. Hoppe, R. Point Comfort, Refining Bauxite to Alumina — 
the Midpoint Between Mine and Metal. Eng. and Min. J., 
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7. Husted, J. E. Potential Reserves of Domestic Non- 
Bauxltlc Sources of Aluminum. Met. Soc. AIME, Paper A74- 
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8. International Bauxite Association. Quarterly Review. 
V. 5, Nos. 2 and 3, December 1979-March 1980, 52 pp. 

9. . Quarterly Review. V. 5, No. 4, June 1980, 39 pp. 

10. Kellogg, H, H. Sizing Up the Energy Requirements for 
Producing Primary Materials. Eng. and Min. J., April 1977, 
pp. 61-65. 

11. Kurtz, H. F. Aluminum and Bauxite chapters in: Minerals 
Commodity Summaries 1980. U.S. Bureau of Mines, Washing- 
ton, D.C, January 1980, 191 pp. 

12. Malenbaum, W. World Demand for Raw Materials in 
1985 and 2000. McGraw-Hill Book Co., Inc., New York, 1978, 
126 pp. 

13. Metal Bulletin Ltd. World Aluminum Survey 1977. 
London, 1978, 199 pp. 

14. Metals Week. Aluminum. V. 50, No. 3, Jan. 15, 1979, 
10 pp. 

15. Mining Journal (London). Aluminum: A Decade of 
Change. V. 294, No. 7541, Feb. 29, 1980, pp. 153-155. 



16. Nunn, R. R. The Comparative Economics of Producing 
Alumina From U.S. Non-Bauxltic Ores. Met. Soc. AIME, Paper 
LM-A-15, 1979, pp. 283-334. 

17. Peterson, G. R. The International Bauxite Association 
and Its Implications for the Aluminum Industry. M.S. Thesis, 
Colorado School of Mines, Golden, Colo., 1980, 181 pp. 

18. Radetzki, M. Market Structure and Bargaining Power. 
Resources Policy, June 1978, pp. 115-125. 

19. St. Clair, H. W. Operation of Experimental Plant for 
Producing Alumina From Anorthoslte. BuMlnes Bull. 577, 
1959, 129 pp. 

20. Stamper, J. W., and H. F. Kurtz. Aluminum. BuMlnes 
Miner. Commodity Profiles, May 1978, 29 pp. 

21. Stermole, F, J. Economic Evaluation and Investment 
Decision Methods. Golden, Colo., 1974, 443 pp. 

22. STRAAM Engineers Inc. Capital and Operating Cost 
Estimating System Manual for Mining and Beneficiatlon of 
Metallic and Nonmetallic Minerals Except Fossil Fuels In the 
United States and Canada. Submitted to the BuMines under 
contract J0255026, December 1977, 374 pp. Available from 
the BuMlnes, Minerals Availability Field Office, Denver, Colo. 
Also available as: 

Clement, G. K., Jr., R. L. Miller, P. A. Seibert, L. Avery, and 
H. Bennett. Capital and Operating Cost Estimating System 
Manual for Mining and Beneficiatlon of Metallic and Non- 
metallic Minerals Except Fossil Fuels in the United States and 
Canada. BuMlnes Special Pub., 1980, 149 pp. 

23. U.S. Bureau of Mines. The Bureau of Mines Minerals 
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IC 8654, 1974, 199 pp. 

24. . A Dictionary of Mining, Mineral, and Related 

Terms. Washington, D.C, 1968, 1,269 pp. 

25. . Minerals and Materials/A Monthly Survey. Wash- 
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26. U.S. Environmental Protection Agency. Development 
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facturing Point Source Category. Washington, D.C, March 
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Reserve Classification for Minerals. Circ, 831, 1980, 5 pp. 

28. Wilson, L. L. Aluminum — Bright Spot In the Economy. 
Min. Cong. J., December 1979, pp. 33-36. 



21 



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